Automatic arc welding



Ag. 6 1940- o. wElGNER AUTOMATIC ARC WELDING Filed Nov. l9, 1937 2Sheets-Shes?l l a r e md 3 m 52:1 0 y M 5, f1@ WT@ U1 2 #1, Al. E. 4 E.f f 5 .MJHHHHHMEHMw/ mi U D J H l ma UNITED 'STATES PATENT oFFlcsAUTOMATIC Anc WELDING Otto Weigner, Vienna, Austria, assignor to Elin A.G. fr elektrische Industrie, Vienna-Weiz, (Styria) Austria, acorporation or Austria Application November 9, 1937, serial No. 173,617

In Austria November 14, 1936` 12 Claims. (Cl. 21S-8) This inventionrelates to thefeeding of electric cutting edges wear away very rapidly,and even current and the transmission of the advancing when the edgesare new particles of the covering movement,to covered electrodes used inautocomposition become lodged between the cutting matic welding. It'isknown to feed the welding edges and the electrode core, which is detrilcurrent to rigidly and current-conductively intermental to the propertransmission of current to connected covered electrodes only at spacedthe electrode, causes the cutting edges to heat, bared points on theelectrodes, either by means and in view of the high current strengths ofsevof pins joining the electrodes or by means of eral hundred amperesused contributes still furmetal chaplets (plates) clamped between eachther to the destruction of the sharp edges.

electrode and the next. For this purpose the According to thepresentinvention the known 10 advancing of the electrodes is effectedeither-by arrangement referred to at the outset isimmeans of an endlessband or by means of a screw proved upon, the spacing 0f the points 0fContact threaded spindle in which the pins or chaplets for the currentfeed rendered independent of engage, the-,- drive of the advancingmechanism the length of the electrodes, and the welding with 1l beingcontrolled automatically in dependence on endless covered electrodesfacilitated, by provid- 15 the voltage of the electric arc. ing baredspots in the covering extending in as For the mechanical and electricalinterconfar as up to the electrode core and causing the. necting of thecovered electrodesv various methsimultaneous transmission of current andof the ods, such as screwing together, fitting together, feed oradvancing movement of theelectrodes or welding together, have beenproposed. to be effected by means of elements which are 20 Theincreasing of the admissible current load neither involved in theproduction or forming of makes it desirable tobring the points at whichthe bared spots nor restricted to the points of current is fed to theelectrodes nearer together 'interconnection between the electrodes, thebared than corresponds to the usual length of welding spots beingequally spaced at a distance apart electrodes, viz., 350-450 mm. It isalso desirable that may be determined at will. 25 to be able to useendless covered electrodes, of theA The elements contemplated for thispurpose type supplied in rings, in automatic electric arc are forvinstance slotted small metal plates or welding. chaplets, driversresliently pressed on, or the It is already known to enable endlesselectrodes turns of the thread on a screw spindle, all these 3o to beused in automatic welding by removing elements being' capable of beingbrought tem- 30 some of the covering continuously in an axial p'orarilyand repeatedly into close and perfect direction down 'the length of theVelectrode by electric contact with the core of the electrode, ymeans ofa milling` cutter in the welding head, but not' having to enter thewelding zone and and feeding the current to 'the bared track thus bewelded along with the vmaterial of the obtained, with the aid ofbrushes. Apart from` electrode. j 35 the inevitable damage of a seriousnature done 'I'here thus results, of necessity, an improveto the crumblycovering composition and the ment in the quality 0f the Weld, asCOmpaIed covering of alltheparts of the welding head with that obtainedby the previously known with dust resulting from this method thecommethod on which the present invention provides 40 bining of currentfeed and electrode advancing an improvement, since in the irst place therisk 40 is not feasible, and the wear on the brushes is of flaws in theseam due to the Weldingin of the very heavy. Moreover, in the case ofthin coated driving chaplet (plates), which is after all of electrodesthis method of effecting the'v feed considerable size compared with thecross-seccauses an appreciable part of the covering to go tional area ofthe electrode core,.is eliminated,

to waste with the result that the quality of the While in the secondplace the Apossibility 'is also 45 welding seam is not as good as itotherwise .provided of welding with alower current strength would be.than would be necessary for welding in the driv- A further priorproposal, according to which ing chaplet (plates), which in its turnmakes it rollers with a cutting edge and mounted on a possible for therst time for small section elecwheel are pressed into the covering andin this y trodes to be used in automatic welding. '50

manner the feeding of current to the electrode The baring of 'spacedportions ofthe surface and the advancing of the electrode effected in ofthe electrode core may be effected in the one operation, has not provedsatisfactory in course-of the manufacturing of the electrodes, practiceeither. Owing to the hardness of the or alternatively may be carried outprior to the generally crystalline covering composition the introductionof the electrodes into the automatic 55 welding machine by the formationof longitudinal or peripheral slots through the covering, or againduring the welding operation by means of a milling or cutting deviceattached to the automatic welding machine, for which purpose thisattachment takes its drive positively from the drive of the advancingmechanism and is brought up to the electrode at stated intervals.

To enable slotted current-feeding and electrede-driving chaplets(plates) `to be used the electrode is preferably bared at two oppositepoints on its periphery, while for use 'with current-conducting drivingelements of other than slotted shape it maysuffice to bare the electrodecore by cutting away the covering at intervalsK on ones'ide only.

gage in a feed or advancing device which may be 0f conventional design.

The detaching of the slotted chaplets (plates) after clearing theadvancing mechanism and the current feed bars is effected by suitablewiping or ejecting-means which may -be coupled with a deviceforinserting-thechaplets (plates) from a supply stack, and that in suchamanner during the advancing of the electrodes that at least one" chaplet(plate) at a time touches the current conducting bars and engages in theadvancing mechanism. Both the current feed and the advancing of theelectrode are thus free of interruption throughout the entire weldingoperation. Instead of or in addition to the baring Aslots in theelectrode covering, the described driving and current-conducting'chaplet (plate) may yof course also be applied to current-conductingconnecting piecesused to join the electrodes together end to end.--lin-this case short end portions of the covered electrodes are bared bycutting or grinding andl joined together by the connecting sleeves.Thesleeves them'lves are furnished with the slots required for theengagement of the driving and current-conducting elements.

If elastic driving elements are employed as'current-conductingmembers-which are pressed up; against bared portions of the coveredelectrode and thus positively ensure close contact and `reliableadvancing of the electrode, there are preferably providedcounter-supporting rollers to save' the electrode from becoming bent, oralternatively `there are used two endless bands with sprung drivingelements as current-conducting members erably'made hollow, andwater-cooled, from some metal, suchas a copper alloy, which is a goodconductor of electricity. By providing, above the current feedingspindle, a spindle made of tool steel andhaving serrated screw threadingof the same pitch as the conductor spindle, and rotating this spindlewith the former the cutting of the required slots in the covering at theproper intervalsmay be eiected in a simple manner.

Constructional `examples are given, by way ofl illustrating theinvention, in the' accompanying drawings.

Fig. 1 is a detail side elevation of a covered electrode havingdiametrically disposed slots at intervals, one being shown with aslotted plate in position and another being shown without the slottedplate. v V

Fig. 1A is a horizontal section through the electrode at one of theslotted areas. Y

Fig. 1B is an edge view of one of the slotted plates.

Fig. 1 is a top plan view of the slotted plate.'

Fig. 2 is a detail horizontal section showing the electrode, the feedscrew, the current supply bars in section and a slotted plate in plan;this figure shows the co-relation of the parts mentioned, in theiroperative positions.

Fig. 3 is a detail vertical section of the ends of two electrodes with ajoining sleeve or ferrule.

Fig. 3A is a cross section on the line (iA-3A of Fig. 3.

Fig. l4 issa diagrammatic side elevation .of the apparatus employing theparts such as are shown in the preceding gures.

Fig. 4A is a diagrammatic detail plan on the line IIL-Moi' Fig. 4.

Fig. 5 is a diagrammatic side elevation and part section of amodication.

. Fig. 6 is a view similar to Fig. ,'5.of a further modification.

Refening to Figs. 1 and 2 of these drawings, the electrode I is providedwith bared recesses or gaps Ia in which there engage the slottedchaplets (plates) 2 which in their turn are connected both with-thescrew threaded spindle 3 for transmitting the advancing movement andalso with current supply bars I.

, In the form shown in Fig. 3 the joining sleeve or ferrule 5 isutilized for current conducting and the transmission of advancingmovement, it being advisable to provide, in addition to this oneengaging point, further engaging points spaced like these shown in-Fig.l.

the two cutters G alternately towards and away from the electrode. Inthis manner cuts are made in the covered electrode at any desiredintervals depending on the adjustment of the crank gear.

Fig. 5vshows a form of construction embodying the use of resilientypressed up driving' elements secured, in uniformly spaced relation, on aband, chain, wire cord, or the like.

Fig. 6 shows the use of a screw-threaded spindle I5 for advancing andfeeding current to the electrode, and having a screw-threaded elementI6' having its thread provided with cutting edges IIx for the productionof the bared places. 'Ihe feeding spindle I5 is supported by thebearings I8 and 2li, which bearings may also serve for sup plying thecurrent. Driving ,is effected by any suitable motor (not illustrated)acting by means of suitable gearing on the toothed wheel I1 of thespindle. The element I6 preferably -conslsts of hardened tool steel.

leads through the stuillng box I9 into'the hollow, interior of vthespind1e I5 Aand. provides for the iiowing in and oi of the cooling.water. Also The tubular system 2I here the electrode is supported bycounter rollers S3 .In Figs. 5 and 6 of the drawings there areA showncounter-supporting rollers I3 which are provided for the purpose ofpreventing the electrode from becoming bent or buckled by pressureexerted thereon from one side only.

Having now particularly described and ascertained the rature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is: y

1. In electric welding apparatus using a covered electrode, a weldinghead, a cutting device in said welding head for the production of baredplaces on the electrode, said places being spaced irrespectively of thelength of the electrode, said cutting' device having cutters rotating inplanes crossing the longitudinal axis of the electrode so as to obtainbared places of comparatively small longitudinal extension and movingmeans mechanically coupled with said cutting device and automaticallycoming into electrical Contact with said bared places, saidmeansproviding simultaneously for feeding current to as well as for advancingthe electrode.

2. In electric welding apparatus using rodshaped electrodes, a weldinghead, means for the rigid and current-conducting interconnection of thesaid electrodes,v current-leading elements conduct'ively and positivelymechanically connected to the core of the said electrodes, at previouslybared places spaced irrespectively of the length of the electrodes,electric conductors extending parallel to the said electrodes for adistance greater than the clearance between any consecutive two of thesaid elements, means for securing electrical contact between the saidconductors and the said elements, means for feeding forward the saidelements, and meansin the said welding head for producing theisaid baredplaces on the electrodes, means to project and retract said last namedmeans to place same in its operative and non-operative positionsrespectively, and a single motor for operating said projecting andretracting means and said electrode elements feeding means.

' 3. In electric welding apparatus using covered rod shaped electrodes,means for the rigid and current-conducting interconnection cf the saidelectrodes, current-leading elements conductively and positivelymechanically connected to the core of the said electrodes, at previouslybared places spaced irrespectively of the length of the electrodes,electric conductors extending parallel to the said electrodes for adistance greater than the clearance between any consecutive two of thesaid elements, means for securing electrical contact between the saidconductors and the said elements, means for advancing the said elements,and a cutting device comprising a rotary cutter, a motor to rotatesaidcutter, and

driving means cooperative with said advancing means for bringingsaidcutting device to bear against said electrodes at intervals.depending upon the rate of advancing said electrodes.

4. In electric welding apparatus using covered rod shaped electrodes,means for the rigid and current-conducting interconnection of the saidelectrodes, current-leading elements conductively andpositivelymechanically connected to the core of the said electrodes atpreviously bared places, spaced irrespectively of the length of theelectrodes, electric conductors extending parallel to the saidelectrodes for a distance greater than the clearance between anyconsecutive two of the said elements. means for securing electrical saidelements, means comprising a screw spindle for advancing the saidelements and a cutting device, movable up to and away from the saidelectrodes comprising a rotary cutter, a motor for' rotating said cuttergearing operatively coupled with said cutting device and with said screwspindle, and adapted to control the bringing up yplaces on saidelectrode, said places being spaced irrespectively of the length of theelectrode, said cutting device having cutters rotating in planescrossing the longitudinal axis of the electrode so as to obtain baredplaces of comparatively small longitudinal extension, means providingfor feeding current to and advancing the electrode, said meanscomprising current-leading elements conductively and positivelymechanically connected to the core of said electrode at the said baredplaces, electrical conductors extending parallel to the said electrodefor a distance greater than the clearance between any consecutive two ofthe said elements, means for securing electrical contact between thesaid conductors and the said elements'and means for feeding forward thesaid elements, means to project and, retract said cutting means to placevit in its operative and nonoperative position, respectively, and asingle motor for operating said projecting and retracting means and saidlast named feeding means.

6. In electric welding apparatus using covered rod-shaped electrodeshaving previously bared places spaced irrespectively of the length ofthe electrodes, means to secure electrical contact with said electrodessimultaneously at two or more spaced bared places and to advance saidelectrodes, said means comprising a screw spindle of goodcurrent-conducting material for current feeding and for advancing theelectrode, the threads of the screw lying `in said bared places, andmeans to hold said electrodes with the bared areas of their cores incontact with the threads vof said screw spindle.

'7. In electric welding apparatus using covered rod-shaped electrodes,having previously bared places spaced irrespectively of the length ofthe electrodes, means for applying current to the core of saidelectrodes for a distance along the 'electrodes greater than the spacebetween any the electrodes from becoming bent.

- contact between the said conductors the 8. Means to f eed and effectelectrical connecv ing to claim 5, the use of chaplets as currentleading elements, said chaplets being made of good current-conductingmaterial' and being slotted, and adapted to be tted to the previouslyproduced narrow bared places on the electrode and to engage in -thedriving elements ofthe advancing mechanism, preferably a screw-threadedspindle.

11. In an electric welding apparatus using a covered electrode, awelding head, a cutting device in said welding head for the productionof bared places on the electrode, said places being spacedirrespectively of the length of the eiectrode, said cutting devicehaving cutters rotating in planes crossing the longitudinal axis of theelectrode so as to obtain bared places of comparatively smalllongitudinal extension and moving means providing simultaneously forfeeding current to as well as for advancing the electrode,

said means comprising a rotating screw-spindle of goodcurrent-conducting material mechanically coupled with said cuttingdevice so that the threads of the screw-spindle will come intoengagement with said bared places, and means to hold said electrode withthe bared areas of. its core in contact with the threads of said screwspindle.

12. In an electric welding yapparatus usinga covered electrode, awelding head, a cutting device in said welding head for the productionof bared places on the electrode, said places being spacedirrespectively of the length of the electrode, said cutting deviceconsisting of a rotating spindle disposed parallel to the said electrodeand having a cutting screw threading, moving means

